JPH08294286A - Inverter apparatus - Google Patents

Abstract

PURPOSE: To realize reduction in size of the apparatus as a whole and fabrication cost thereof by simplifying a structure of the power supply for driving a switching element. CONSTITUTION: An inverter apparatus is formed in the structure that six IGBT 3 to 8 are connected, by the 3-phase bridge connection, between a positive power supply line 1 and zero-potential power supply line 2 and a control signal from a control circuit is applied to the gates of IBGT 3 to 8 through photocouplers 25, 29, 32, 35 to 37. Moreover, a DC power supply circuit 45 is provided as the common power supply for driving the gates of the zero potential side IGBT 4, 6, 8 and the drive capacitors 50, 53, 56 are also provided as the power supplies to drive the gates of the positive side IGBT 3, 5, 7. In addition, charging circuits 52, 55, 58 are also provided to charge the drive capacitors 50, 53, 56 from the DC power supply circuit when the zero-potential side IGBT 4, 6, 8 turn on.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device suitable for use in variable speed control of, for example, a three-phase induction motor or a three-phase brushless motor.

[0002]

2. Description of the Related Art As an inverter device of this type, for example, 3
An example of the phase inverter device is shown in FIGS. 6 and 7. First,
In FIG. 6 schematically showing the main circuit configuration of the inverter device,
Between the positive-side power supply line 1 and the zero-potential-side power supply line (negative-side power supply line) 2 led from the DC power supply, a pair of switching elements connected in series, for example, IGBTs 3 to 8 are connected in three pairs in parallel. It is installed in. In this case, the positive side IGBTs 3, 5,
7 and the zero-potential side IGBTs 4, 6 and 8 at connection points A, B and C
Are U-, V-, and W-phase output terminals, respectively. still,
Freewheel diodes 9 to 14 are connected to both ends of each of the IGBTs 3 to 8 with the illustrated polarities.

Further, the control circuit for ON / OFF controlling each of the IGBTs 3 to 8 sends a control signal to the three positive side IGBTs 3,
Positive side drive circuits 15 and 1 for the gates 5 and 7, respectively.
6 and 17 and gate resistors 18, 19 and 20 are provided. The control circuit is configured to give a control signal to the gates of the three zero-potential-side IGBTs 4, 6, and 8 via a common zero-potential-side drive circuit 21 and gate resistors 22, 23, and 24. Has been done. Here, specific configurations of the positive side drive circuits 15, 16 and 17 and the zero potential side drive circuit 21 will be described with reference to FIG.

As shown in FIG. 7, the positive side drive circuit 15 has a photocoupler 25, which is an optical insulating element, and a DC power supply circuit 26 for applying a DC voltage to a photodetector element side circuit 25a of the photocoupler 25. Is configured. The light emitting element 25b of the photo coupler 25 is controlled to emit light by a control signal from the control circuit. That is, the control signal from the control circuit is applied to the gate of the IGBT 3 via the photocoupler 25, so that the IGBT 3 is on / off controlled. The DC power supply circuit 26 is
The power source for driving the IGBT 3 is configured, and includes a secondary winding 27 a of the power transformer 27 and a full-wave rectifying / smoothing circuit 28. This full-wave rectifying / smoothing circuit 28
Is two diodes 28a, 2 of center tap type.
8b and two smoothing capacitors 28c and 28d.

Similarly, the positive side drive circuit 16 is configured to have a photocoupler 29 and a DC power supply circuit 30. Then, the DC power supply circuit 30 includes the power supply transformer 2
7 secondary winding 27b and a full-wave rectifying / smoothing circuit 31. The full-wave rectifying / smoothing circuit 31 includes two diodes 31a and 31b and two smoothing capacitors 31.
It is composed of c and 31d. The positive side drive circuit 17 is configured to include a photo coupler 32 and a DC power supply circuit 33. Then, the DC power supply circuit 33
Is composed of a secondary winding 27c of the power transformer 27 and a full-wave rectifying / smoothing circuit 34. The full-wave rectifying / smoothing circuit 34 is composed of two diodes 34a and 34b and two smoothing capacitors 34c and 34d.

Further, the zero potential side drive circuit 21 includes three photocouplers 35, 36 and 37 and light receiving element side circuits 35a, 36a and 3 of these photocouplers 35, 36 and 37.
7a, and a DC power supply circuit 38 for applying a DC voltage. The DC power supply circuit 38 includes a secondary winding 27d of the power supply transformer 27 and a full-wave rectifying / smoothing circuit 39. This full-wave rectifying / smoothing circuit 39 includes two diodes 39a and 39b and two smoothing capacitors 3
It is composed of 9c and 39d.

In the case of the above configuration, the positive side IGBTs 3, 5, 7
DC power supply circuits 26, 30, 3 which are power supplies for each drive of
3 are insulated from each other. Furthermore, the zero potential side IGBT
DC power supply circuit 3 which is a common power supply for 4, 6 and 8 drives
The reference numeral 8 is insulated from the three DC power supply circuits 26, 30, 33. The power transformer 27 has a primary winding in addition to the above four secondary windings 27a to 27d, and the secondary winding is controlled by controlling the primary winding side by some means. It is configured to stabilize the secondary voltage on lines 27a-27d.

[0008]

However, in the above-mentioned conventional configuration, the three DC power supply circuits 26, 30, 33 as power sources for driving the positive side IGBTs 3, 5, 7 and the zero potential side IGBTs 4, 6, Since one DC power supply circuit 38 as a common power supply for drive 8 is required, there are drawbacks that the structure for the DC power supply circuit becomes complicated and the number of constituent parts increases. Specifically, as the power transformer 27, one having four secondary windings 27a to 27d must be used, and the configuration of the power transformer 27 becomes large, and the configuration of the entire device can be made compact. In addition to being an obstacle, it was a factor of increasing the manufacturing cost.

Therefore, an object of the present invention is to provide an inverter device in which the structure of a power source for driving a switching element can be simplified, the size of the entire device can be reduced, and the manufacturing cost can be reduced.

[0010]

The inverter device of the present invention comprises a pair of switching elements connected in series and arranged in parallel between a positive side and a zero potential side of a DC power source. In addition, in the inverter device configured to give the control signal output from the control circuit for ON / OFF controlling each switching element to the control terminal of each switching element via the optical insulation element, drive the zero-potential side switching element. The common power supply for the drive, which is used as a power supply for applying to the control terminal when it operates, and which is commonly used by all the zero potential side switching elements, and its control when driving each positive side switching element. The drive capacitor, which is the power supply for applying to the terminals, and the drive common power supply when the zero potential side switching element is turned on. To charge the drive capacitor positive side switching elements constituting the turned-on zero potential switching device pair having characterized in that and a charging circuit.

In the case of the above configuration, the main circuit zero potential of each of the zero potential side switching elements and the zero potential of the control signal system of the control circuit may be connected in common. Further, it is also preferable to include a protection circuit for forcibly turning off the positive side switching element when a voltage between terminals of the drive capacitor is lower than a set voltage.

[0012]

According to the above means, when the zero potential side switching element is turned on by the charging circuit, the drive capacitor is charged from the common drive power source for the zero potential side switching element and the positive side switching element is driven. The drive power supply for applying to the control terminal is constituted by the drive capacitor. In the case of this configuration, the common power source for driving the zero-potential side switching element can be used as the power source for driving the positive side switching element, so that the configuration of the drive power source can be simplified. Specifically, when focusing on the power transformer that constitutes the drive power source, only one secondary winding is required to configure the drive common power source for the zero-potential side switching element, and the remaining secondary windings are required. Since the winding can be eliminated, the power transformer can be downsized.

Further, in the above configuration, when the main circuit zero potential of each zero potential side switching element and the zero potential of the control signal system of the control circuit are connected in common, the control of each zero potential side switching element is performed. The optical insulation element between the terminal and the control circuit can be eliminated, and the cost can be reduced accordingly. Furthermore, if a configuration is provided in which a protection circuit that forcibly turns off the positive side switching element when the voltage between the terminals of the drive capacitor is lower than the set voltage is provided, the positive voltage is maintained when the voltage between the terminals of the drive capacitor is sufficiently high. Since the side switching element is driven and controlled, the positive side switching element can be stably driven and controlled.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a three-phase inverter device will be described below with reference to FIG.
The same parts as those in the conventional configuration shown in FIGS. 7 and 8 are designated by the same reference numerals. That is, in the first embodiment, as shown in FIG. 1, six IGBTs 3 to 8 are so-called three-phase bridge connection between the positive side power source line 1 and the zero potential side power source line 2 led from the DC power source. And constitutes the main circuit. Each I above
A freewheel diode 9 is provided on both ends of the GBTs 3 to 8.
~ 14 are connected.

The control circuit for ON / OFF controlling each of the IGBTs 3 to 8 outputs a control signal to the three positive side IGBTs 3, 5, and 7.
Positive side drive circuits 41, 42, 43 for the gate of
And gate resistors 18, 19, 20. In addition, the control circuit applies a control signal to the gates of the three zero-potential-side IGBTs 4, 6, and 8 that are common to the zero-potential-side drive circuit 44 and the gate resistors 22 and 23.
It is configured to be provided via 24. Here, the zero-potential side drive circuit 44 has almost the same configuration as the zero-potential side drive circuit 21 of the conventional configuration. First, the specific configuration of this circuit 44 will be described.

The zero potential side drive circuit 44 includes three photocouplers 35, 36 and 37 and these photocouplers 3.
5, 36, 37 light receiving element side circuits 35a, 36a, 37
and a DC power supply circuit 45 for applying a DC voltage to a. The DC power supply circuit 45 constitutes a common power supply for drive and is composed of a secondary winding 46 a of a power supply transformer 46 and a half-wave rectifying / smoothing circuit 47. The half-wave rectifying / smoothing circuit 47 includes the secondary winding 46a.
It is composed of a diode 48 and a smoothing capacitor 49 which are connected in series between both terminals. In this case, the intermediate connection point D1 between the diode 48 and the smoothing capacitor 49 constitutes the positive side terminal, and the intermediate connection point D2 between the smoothing capacitor 49 and the secondary winding 46a constitutes the negative side (zero potential side) terminal. ing. The positive terminal D1 of the DC power supply circuit 45 is connected to the light receiving element side circuit 35a of the photocouplers 35, 36 and 37,
36a and 37a are respectively connected to the positive side terminals, and the zero potential side terminal D2 is connected to the zero potential side terminals of the light receiving element side circuits 35a, 36a and 37a, respectively. Further, the zero potential side terminal D2 of the DC power supply circuit 45 is connected to each emitter of the IGBTs 4, 6, 8 (that is, the zero potential side power supply line 2).

The power transformer 46 has a single secondary winding 46a and is smaller than the conventional power transformer 27. Further, the light emitting elements 35b, 36 of the photocouplers 35, 36, 37 are
b and 37b are configured so that light emission is controlled by a control signal from the control circuit. That is, the control signal from the control circuit is transferred to the IG via the photo couplers 35, 36 and 37.
By being applied to the gates of BT4, 6 and 8, I
The GBTs 4, 6 and 8 are controlled to be turned on and off.

Next, the positive drive circuit 41 will be described. The positive side drive circuit 41 includes a photo coupler 25.
And a drive capacitor 50 for applying a DC voltage to the light receiving element side circuit 25a of the photocoupler 25. This drive capacitor 50 is a positive side IG
The power source is configured to be applied to the gate of the BT3 when it is driven. The positive side terminal (upper side terminal in FIG. 1) 50a of the drive capacitor 50 is connected to the positive side terminal of the light receiving element side circuit 25a of the photocoupler 25, and the zero potential side terminal (lower side terminal in FIG. 1). ) 50b is connected to the zero potential side terminal of the light receiving element side circuit 25a. Further, the zero potential side terminal 50b of the driving capacitor 50
Is the emitter of the positive side IGBT 3 (that is, the positive side IGBT 3
Is connected to an intermediate connection point A) between the IGBT 4 and the zero potential side IGBT 4.

In addition, the positive side terminal 50a of the drive capacitor 50 and the positive side terminal D of the DC power supply circuit 45.
The diode 51 having the polarity shown in the figure is connected between 1 and 1. As a result, when the zero potential side IGBT 4 is turned on, the DC power circuit 45 drives the drive capacitor 50.
A charging circuit 52 for charging the battery is formed. After the drive capacitor 50 is charged, the charge of the drive capacitor 50 serves as a power source for applying the charge to the gate of the positive side IGBT 3 when it is driven. The light emitting element 25b of the photocoupler 25 is controlled to emit light by a control signal from the control circuit. That is, the control signal from the control circuit is
The IGBT 3 is configured to be ON / OFF controlled by being applied to the gate of the IGBT 3 via the photocoupler 25.

Similarly, the positive side drive circuit 42 includes a drive capacitor 5 for applying a DC voltage to the photocoupler 29 and the light receiving element side circuit 29a of the photocoupler 29.
And 3. This drive capacitor 5
3 is connected to the positive side terminal of the light receiving element side circuit 29a of the photocoupler 29, and the zero potential side terminal 53b is connected to the zero potential side terminal of the light receiving element side circuit 29a. The zero potential side terminal 53b of the driving capacitor 53 is connected to the emitter of the positive side IGBT5 (the positive side IGBT5
Is connected to the intermediate connection point B) between the IGBT 6 and the zero potential side IGBT 6. Further, a diode 54 having the illustrated polarity is connected between the positive side terminal 53a of the drive capacitor 53 and the positive side terminal D1 of the DC power supply circuit 45.
As a result, when the zero potential side IGBT 6 is turned on, the charging circuit 55 that charges the drive capacitor 53 from the DC power supply circuit 45 is formed. After the drive capacitor 53 is charged, the charge stored in the drive capacitor 53 serves as a power supply for applying to the gate of the IGBT 5 when driving it.

Similarly, the positive side drive circuit 43 includes a photo coupler 32 and a light receiving element 32 of the photo coupler 32.
and a drive capacitor 56 for applying a DC voltage to a. The positive-side terminal 56a of the drive capacitor 56 is the light-receiving element side circuit 32 of the photocoupler 32.
The zero potential side terminal 56b is connected to the positive side terminal of a, and the zero potential side terminal 56b is connected to the zero potential side terminal of the light receiving element side circuit 32a. Then, the zero potential side terminal 56b of the drive capacitor 56
Is connected to the emitter of the positive side IGBT 7 (intermediate connection point C between the positive side IGBT 7 and the zero potential side IGBT 8).
Further, the positive side terminal 56a of the drive capacitor 56 is
, And the diode 57 of the polarity shown in the figure between the positive side terminal D1 of the DC power supply circuit 45. As a result, when the zero potential side IGBT 8 is turned on, the charging circuit 58 that charges the drive capacitor 56 from the DC power supply circuit 45 is formed. Then, after the drive capacitor 56 is charged, the charge stored in the drive capacitor 56 serves as a power supply for applying the charge to the gate of the IGBT 7 when it is driven.

In the case of the above configuration, the positive side IGBT3,
The drive capacitors 50, 53, and 56, which are the power supplies for the drives 5 and 7, are isolated from each other by the diodes 51, 54, and 57 and are independent of each other. In the above configuration,
The photocouplers 25, 29, 32, 35, 36, 37 insulate the control circuit side potential and the main circuit side potential. The power transformer 46 has a primary winding in addition to the secondary winding 46a, and the secondary winding of the secondary winding 46a is controlled by controlling the primary winding side by some means. It is configured to stabilize the voltage.

However, according to the present embodiment having the above-mentioned structure, when the zero potential side IGBTs 4, 6, 8 are turned on, the DC power supply circuit 45 drives the driving capacitor 50,
It is charged to 53 and 56. As a result, each positive side IGBT
When driving 3, 5 and 7, drive capacitor 5
Since 0, 53, 56 serve as a power source for applying to the gates of the respective IGBTs 3, 5, 7, the control circuit thereafter supplies the control signals via the photocouplers 25, 29, 32 to the positive side IGBTs 3, 5 ,,. It is possible to control ON / OFF of the positive side IGBTs 3, 5, and 7 by applying the same to the gate of No. 7.

In the first embodiment, the positive IG
Drive capacitors 50, 53 and 56 are provided as drive power sources for the BTs 3, 5 and 7, and the zero potential side IGBT4,
The drive capacitors 50, 53, and 56 are charged by the charging circuits 52, 55, and 58 from the DC power supply circuit 45, which is the common power source for driving 6 and 8. As a result, the DC power supply circuit 45 can be used as a drive power supply for the positive side IGBTs 3, 5 and 7,
It is possible to simplify the configuration of the drive power supply.
Specifically, focusing on the power supply transformer 46, only one secondary winding 46a is required to form a drive common power supply for the zero potential side IGBTs 4, 6 and 8, and the remaining secondary windings are required. Since the wires can be eliminated, the power supply transformer 46 can be downsized as compared with the conventional configuration (see FIG. 7). Therefore, it is possible to reduce the size of the entire inverter device and reduce the manufacturing cost.

FIG. 2 shows a second embodiment of the present invention, and the difference from the first embodiment will be described. The same parts as those in the first embodiment are designated by the same reference numerals. In the second embodiment, the photocouplers 35, 3 are provided between the gates of the zero potential side IGBTs 4, 6, 8 and the control terminal of the control circuit.
Instead of disposing 6, 37, amplifier circuits 59, 60, 6
1 is provided. These amplifier circuits 59,
Positive side terminals (power input terminals) 59a, 60 of 60, 61
a and 61a are connected to the positive side terminal D1 of the DC power supply circuit 45, and the zero potential side terminals 59b, 60b and 61b are the zero potential side terminal D2 of the DC power supply circuit 45 (that is, the zero potential side power supply line 2).
It is connected to the. The amplifier circuits 59, 60, 61 are
The control signals (ON / OFF command signals) received from the control circuit are amplified and given to the gates of the IGBTs 3, 5, 7 so that the IGBTs 3, 5, 7 are ON / OFF controlled according to the control signals. .

In the second embodiment, the zero potential side I
The main circuit zero potential of the GBTs 4, 6 and 8 (that is, the zero potential side power supply line 2) and the zero potential of the control signal system of the control circuit are commonly connected. Further, with respect to the light emitting elements 25b, 29b, 32b of the photocouplers 25, 29, 32 of the positive side drive circuits 41, 42, 43, their negative side terminals are connected to the zero potential power line 2 and their positive side terminals are connected. Is preferably connected to the control circuit via a current limiting resistor. The configuration of the second embodiment other than the above is the same as the configuration of the first embodiment.

Therefore, also in the second embodiment, it is possible to obtain substantially the same operational effects as in the first embodiment.
Particularly, in the second embodiment, the zero potential side IGBTs 4, 6, 8
The main circuit zero potential (zero potential side power supply line 2) and the zero potential of the control signal system of the control circuit are commonly connected, and the zero potential side IGBT is connected.
Photocoupler 3 between the gates 4, 6, and 8 and the control circuit
5, 36 and 37 can be eliminated, and the manufacturing cost can be reduced accordingly.

FIGS. 3 and 4 show a third embodiment of the present invention, and the difference from the first embodiment will be described. The same parts as those in the first embodiment are designated by the same reference numerals. In the third embodiment, as shown in FIG. 3, the gates of the positive side IGBTs 3, 5, 7 (specifically, the resistor 18,
(19, 20) and the photocouplers 25, 29, 32, respectively, protection circuits 62, 63, 64 are provided. These protection circuits 62, 63, 64 are provided for the positive side IGBTs 3, 5, 7 when the voltage between the terminals of the drive capacitors 50, 53, 56 is lower than a preset voltage.
Has a function to forcibly turn off. Further, since the three protection circuits 62, 63, and 64 have substantially the same configuration, the protection circuit 62 will be representatively described with reference to FIG.

In FIG. 4 showing the protection circuit 62, between the terminals 50a and 50b of the drive capacitor 50,
A Zener diode 65 and an undervoltage detection resistor 66 are connected in series, and a resistor 67 and an NPN type transistor 68 are connected in series. The intermediate connection point between the Zener diode 65 and the undervoltage detection resistor 66 is connected to the base of the transistor 68 via the resistor 69. Further, an NPN transistor 70 for gate cutoff is connected between the output terminal of the light receiving element side circuit 25a of the photocoupler 25 and the terminal 50b of the drive capacitor 50. The base of the transistor 70 is connected to the collector of the transistor 68.

In the protection circuit 62, the voltage across the drive capacitor 50 is zener diode 65.
When the zener voltage is lower than the Zener voltage (set voltage) of the positive side IGBT 3, the transistor 70 is turned on to short-circuit the gate and the emitter of the positive side IGBT 3.
3 is forcibly turned off. After that, when the voltage between the terminals of the drive capacitor 50 exceeds the Zener voltage (set voltage) of the Zener diode 65, the transistor 68 is turned on, and the transistor 70 is turned off. As a result, the control signal from the control circuit is given to the gate of the positive-side IGBT 3 via the photocoupler 25, so that the positive-side IGBT is
3 can be turned on. The protection circuits 63 and 64 have the same configuration as the protection circuit 62 described above. The configuration other than the above is the same as the configuration of the first embodiment.

Therefore, also in the third embodiment, it is possible to obtain substantially the same operational effects as in the first embodiment.
Particularly, in the third embodiment, when the inter-terminal voltage of the drive capacitor 50 is lower than the set voltage, the positive side IGBT 3,
Since the protection circuits 62, 63, 64 for forcibly turning off the transistors 5, 7 are provided, the positive side IGBTs 3, 5, 7 can be stably driven and controlled.

FIG. 5 shows a fourth embodiment of the present invention, and the difference from the third embodiment will be described. The same parts as those in the third embodiment are designated by the same reference numerals. In the fourth embodiment, the photocouplers 35, 3 are provided between the gates of the zero potential side IGBTs 4, 6, 8 and the control terminal of the control circuit.
Instead of arranging 6, 37, the amplifier circuits 59, 60, 61 are provided as in the second embodiment (see FIG. 2). Then, the zero potential side IGBT4,
6, 8 main circuit zero potential (that is, zero potential side power supply line 2),
The control circuit and the zero potential of the control signal system are commonly connected. The configuration of the fourth embodiment other than the above is the same as the configuration of the second embodiment or the third embodiment. Therefore, in the above fourth embodiment,
It is possible to obtain the same action and effect as those obtained in the second embodiment or the third embodiment.

In each of the above embodiments, the IGBT is used as the switching element. However, the invention is not limited to this, and the FET, the bipolar transistor, the thyristor, the GTO or the like may be used.

[0034]

As is apparent from the above description, the present invention charges the drive capacitor from the drive common power source of the zero potential side switching element when the zero potential side switching element is turned on by the charging circuit, When driving the positive-side switching element, the power supply for applying to the control terminal of the positive-side switching element is configured to be taken from the drive capacitor described above, which makes it possible to simplify the configuration of the drive power supply. This has the excellent effect that the power transformer constituting the can be miniaturized.

Further, in the case of the above configuration, when the main circuit zero potential of each zero potential side switching element and the zero potential of the control signal system of the control circuit are commonly connected, the control of each zero potential side switching element is performed. Since the optical insulation element between the terminal and the control circuit can be eliminated, the manufacturing cost can be reduced. Further, when the protective circuit for forcibly turning off the positive side switching element is provided when the voltage between the terminals of the drive capacitor is lower than the set voltage, the positive side switching element can be stably driven and controlled. .

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 3 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.

FIG. 4 is an electric circuit diagram around the protection circuit.

FIG. 5 is a view corresponding to FIG. 1 showing a fourth embodiment of the present invention.

FIG. 6 is a diagram corresponding to FIG. 1 showing a conventional configuration.

FIG. 7 is an electric circuit diagram of a drive power supply.

[Explanation of symbols]

1 is a positive side power supply line, 2 is a zero potential side power supply line, and 3 to 8 are IGBs.
T (switching element), 25, 29, 32, 35, 3
6, 37 are photocouplers (optical insulation elements), 38 is a DC power supply circuit, 39 is a full-wave rectifying and smoothing circuit, 41, 42, 43 are positive side drive circuits, 44 is a zero potential side drive circuit, 45
Is a DC power supply circuit (common power supply for drive), 46 is a power transformer, 47 is a half-wave rectifying and smoothing circuit, 48 is a diode,
49 is a smoothing capacitor, 50 is a drive capacitor,
51 is a diode, 52 is a charging circuit, 53 is a drive capacitor, 54 is a diode, 55 is a charging circuit, 56
Is a drive capacitor, 57 is a diode, 58 is a charging circuit, and 62, 63 and 64 are protection circuits.

Claims (3)

[Claims] 1. A control for arranging a plurality of pairs of switching elements connected in series in parallel between a positive side and a zero potential side of a DC power source, and for controlling ON / OFF of each of the switching elements. In an inverter device configured to give a control signal output from a circuit to a control terminal of each of the switching elements via an optical insulation element, for applying to the control terminal when driving the zero-potential side switching element. A common power supply for drives that is used as a power supply and is commonly used by all zero-potential side switching elements, and a drive that is a power supply for applying to the control terminal when driving each positive side switching element. Capacitor, and the zero potential side switching element that is turned on from the drive common power source when the zero potential side switching element is turned on. An inverter device comprising: a charging circuit for charging a drive capacitor of a pair of positive side switching elements. 2. The inverter device according to claim 1, wherein the main circuit zero potential of each of the zero potential side switching elements and the zero potential of the control signal system of the control circuit are commonly connected. . 3. The inverter according to claim 1, further comprising a protection circuit for forcibly turning off the positive side switching element when a voltage between terminals of the drive capacitor is lower than a set voltage. apparatus.